Malala joins Twitter on her last day of school, receives warm welcome from Bill Gates, Justin Trudeau

Malala Yousafzai, the Pakistani activist and Nobel Peace laureate, celebrated her last day of school in Birmingham, England, on Friday by joining Twitter and the Internet went nuts. Inaugurating her account with a series of tweets, Yousafzai said she was excited about her future, but it was a bittersweet moment knowing many girls would never get the opportunity to finish their education.

Yousafzai was just 11 when she began writing about girls education and life under Taliban rule in north-west Pakistan in a blog for BBC Urdu. In October 2012, a Taliban gunman boarded her school bus in Swat, asked for her by name and shot her in the head. She was flown to the UK to undergo treatment and has been living in Birmingham with her family ever since.

The story of her recovery and survival captivated millions around the world as she took her campaign global and continued to passionately speak out for children's rights and the importance of education for girls.

In 2013, she co-founded the Malala Fund, a non-profit that aims to see a world where "all girls can learn for 12 years and lead without fear." A year later, she became the youngest person to be awarded the Nobel Peace Prize.

In April, she became the youngest UN Messenger of Peace.

"Hi, Twitter", she tweeted on Friday afternoon under the handle @Malala,

"Today is my last day of school and my first day on @Twitter," she wrote. "Graduating from secondary school (high school) is bittersweet for me. I'm excited about my future, but I know that millions of girls around the world are out of school and may never get the opportunity to complete their education.

"Next week, I will be back on my #GirlPowerTrip to meet girls in Middle East, Africa & Latin America. Each girl's story is unique  —  and girls' voices are our most powerful weapons in the fight for education and equality.

Malala's new Twitter account garnered hundreds of thousands of followers within hours and congratulatory messages from numerous global leaders. She even got a formal welcome from Twitter as well.

"You continue to inspire me, @Malala," Billionaire Microsoft co-founder and philanthropist Bill Gates tweeted. "Thanks to you, young women around the world can dream of a brighter future for themselves."

Canadian Prime Minister Justin Trudeau wrote: "Your bravery and commitment to education – both yours & others – is inspiring. Congratulations on graduating high school @Malala!"

So far, Yousafzai has gained over 398,000 followers and counting with her first post retweeted more than 36,000 times. She has been attending the all girls' Edgbaston High School in Birmingham since 2013 and has received an AAA-conditional offer to study Philosophy, Politics, and Economics (PPE) at Oxford's Lady Margaret Hall.

"On and off Twitter, I'm fighting for girls —  will you join me?​" she tweeted.